2023年国家制造业信息化AUTOCAD认证考试样题

Chaｐter1０ＵsingBlｏcｋandExterｎａlRｅferenｃｅs1０.1OverviewAutoCADprovidessｅvｅralfeａturestohelpyｏumａnａgｅobjectsiｎyouｒdｒawinｇs.Withｂloｃksyouｃanoｒganizeaｎdmａｎipulateｍaｎyｏbｊectsasoｎecoｍponent．Youcanａlsｏassocｉatｅｉtｅｍsｏfｉnformａtionwitｈtheｂlｏckｓinyourdrawiｎｇs-ｆorexample，parｔnumｂersandprices-bｙaｔtacｈingａttributes．Sｐecificationｓheetｓorbilｌｓoｆmａterialscanｂecreateduｓingtｈisｉｎｆｏrmation.YｏucanattachoroverlayｅntｉredrawｉnｇsｉnｙoｕｒｃｕrrenｔdrawｉnｇｂyusinｇAｕtoCAＤexteｒnａlrｅｆerences,orxrefｓ.Ｗhenyouopｅnａdraｗingtｈatconｔａinｓxrefs,ａｎychaｎgｅsthathaｖebeｅnmａdeｉntｈereferencedｄrａwingappeａｒiｎthecuｒrｅnｔｄrawiｎg.1０.２ＷorkiｎgwithBlocksＡｂlockisａcｏllectionofobｊectsｙｏｕcanａsｓoｃiａtetｏgｅthertoformasingleobjecｔ,oｒbloｃkdefinｉtion.Youcaniｎseｒｔ,scalｅ，aｎdrｏtaｔeablocｋinadrawing.Youｃanexpｌoｄeａｂlocｋｉｎtoiｔｓcomｐｏnentｏbjｅcts,mｏdifythｅm，andredefｉnetheblock.AutoCADuｐdateｓallcurrentａndfuturｅiｎstaｎcｅsｏｆthatblｏcｋｂasｅdoｎtheblockdeｆｉnition.Ｂlｏcksstｒｅamlinｅｔhedraｗingｐｒocesｓ．Forexample,youcａｎuｓebｌocｋｓtoBuｉlｄastandａrdlibraryoｆｆrｅｑueｎｔlyusedsymbｏls,coｍｐoneｎts,oｒstandardparｔs．Youcaｎinseｒｔthesaｍeｂlocknumerousｔiｍｅsｉnsteadoｆrｅ-cｒeaｔingｔhedrawiｎgeleｍｅntseachtime. Ｒeviseｄraｗingseｆｆiｃｉeｎtｌyｂyｉnserting,rｅｌｏcatinｇ,aｎdｃｏpyingblocksascｏmpｏｎｅｎtsraｔhertｈaｎｉndiｖidｕalgeometrｉcobjectｓ. Savｅdisｋｓpacebysｔorｉｎｇallｒeferenｃｅstｏthesameblockasoneｂlockdefinｉtiｏｎinｔheｄrawｉngdaｔaｂase.Ｆｏｒinｆormａtiｏnaboutｈowtocrｅateaｂloｃｋ,ｓｅe＂DefiｎingBlocks."Wｈenｙoｕinｓertabｌoｃｋｉnyouｒdｒａwinｇ,youarecｒeatingaｂloｃkinｓtance.Eachtimeｙoｕinsｅrtａｂlockinsｔance,ｙouaｓsigｎascalｅｆaｃｔorandrotatｉoｎaｎgletｏtheinseｒteｄｂlock.Youcａnalsｏscaｌｅａbｌocｋｉnstａnceusingdiffｅrｅntvalueｓinanｙｃoordinａte(X，Y,Z)ｄirｅｃtion.Blockｓmaｋeｉtpoｓsibleforyｏutoorganizeyoｕｒｄｒawinｇｔasｋsiｎasystemａｔiｃway,soｔhatyoucansｅtup，ｒedｅsigｎ，andsorｔtｈeobｊeｃtsiｎyourｄraｗingｓaｎdｔｈeｉnfoｒmatｉoｎａssociａｔedwitｈｔhem．DｅfｉningBlocksＹouｃａｎgroupobｊectstoｃｒeatｅｂlockｄefinitｉonsintｈecｕrreｎtdraｗing，oryoｕcansavethｅｂlｏｃkasaseparatedｒaｗinｇｆｉle.Wｈeｎｙoudeｆiｎeａbｌｏｃk,ｙouspeｃｉｆyｔheｂａsepoint,theobｊectstoｇrouｐ,anｄwｈeｔhｅrtｏretａinordeleｔethｅobjｅcｔsｏrcｏnｖerｔthemtoａbｌoｃkinthecｕｒｒｅnｔｄrａｗinｇ.YoucanalsoenｔerａtｅxtdescｒiptｉonａndspecｉfyaｎicｏnuｓedtｏhｅlpiｄeｎtifythｅblｏckdeｆinｉｔiｏninＡutoＣＡDDesignCｅnter.Ｂlｏckｄefiｎitionｓａreoneｏｆmanynongrapｈicalobjｅctssaｖedinadrａwing.See"WｏrkｉｎgwitｈNaｍeｄObｊects."Ｔｏcreａteabloｃkdｅｆｉnｉｔiｏn1ﻩＦroｍtheDrａｗｍenu,chooseＢｌockMake．2ﻩＩntheBｌockDeｆiniｔiｏndiａｌoｇbox,enｔｅranameｆｏｒthｅblｏcｋ.3ﻩUndｅrObjｅｃts,choｏｓｅtheＳelectObjecｔsbｕttｏｎtousethｅpointｉｎgdevicetｏｓｅlectoｂjeｃtsfｏｒtｈｅｂlocｋｄｅfiｎｉtiｏn.Thedialogboxｃlｏsestemporａrｉｌywｈileyｏuselｅｃｔobｊectsｆoｒtheｂlｏｃk.PressENＴEＲｗｈeｎyouaｒedｏnｅsｅlｅctingbloｃks.Theｄiａloｇbｏxrｅｏpenｓ.4ﻩIｆyouwaｎttoｃreateaselｅｃtioｎset,usetheQｕｉcｋＳeleｃtｂuttｏｎtocrｅaｔｅｏrｄefiｎeａfiｌｔerforyoursｅｌeｃtionseｔ.See"ＦiltｅriｎｇSelectionSets."5ﻩUnderObｊects,specifywｈetｈertoretａiｎ，convｅrtｔｏａblock,orｄｅｌetetheselectedoｂｊeｃts．Rｅｔaiｎ:Kｅepｓselｅctedｏbjｅctsｉntheｃurrentdrawinｇ,iｎtｈeｉroriginalｓｔａｔe.ConveｒｔｔoBloｃk:Rｅplａcesselecteｄｏbjectsｗithaｎinｓtancｅofｔhebloｃk．Delｅtｅ:Ｒeｍｏvessｅlecｔedｏbjｅctsafteｒtheblｏckisdefｉned．6 UnｄerBaｓeＰoint,ｅnｔｅrthｅcoordinatevaluｅｓｆortｈｅｉnｓerｔiｏnbａseｐointｏrｃhoosｅtheSpecifyＩnｓeｒｔionBasePｏiｎtbuttontousethepoinｔｉｎｇdｅvice.7ﻩＵnｄerDesｃrｉｐtiｏn,entertextｔohelpidenｔifyｔheblockｆoreasyretrievaｌ．8ﻩUndｅrIcon,sｐecifywhｅtｈｅｒtocreateanicoｎfｒｏｍｔhｅblockdefinitiｏn.Donotｉｎcludeａnicon:Omiｔspreviewiｍａｇefｒｏmｂｌｏckｄefｉｎｉtiｏn.Cｒeａteiｃoｎfrombｌocｋgeｏmetry:Saveｓｐreｖiｅｗimagewｉththebloｃkdefinitiｏn.９ ChoｏseOK．Theblocｋdｅfiniｔionissavedintｈecuｒreｎtdrawｉｎg．Tｏsａveablockorobｊeｃｔasａseｐarａtedｒawingfile1 AttheComｍanｄｐrompt,ｅnteｒwbloｃk.２ InｔｈeＷrｉtｅBｌocｋdiａlｏｇbox，specifｙabｌｏckorａnｏｂｊｅｃtｔowrｉteoｕｔａsａfiｌe.Block:Specifiesablocｋtosaveａsａfile. EntireDrａwｉｎg:Sｅｌｅｃtscuｒrｅntdrａwingaｓablock.ﻩOｂject:Speciｆiesobjeｃtstobesavedasafile. 3ﻩＵnｄerBｌock,seleｃtanamefｒomthｅlisttｏsaveasafiｌe.4ﻩUnderBasePoint，uｓethePiｃｋPointbuｔtｏｎtodefiｎethｅbasｅｐoint．５ UnｄerOｂjecｔs，useｔheSeleｃtｏbｊecｔsbuｔｔoｎtｏseｌｅｃttheobjｅctfoｒthｅblocｋfile．6 Eｎteranamｅfortｈenewｆｉｌｅ.Ifabｌockisselected,WBLOCKaｕtomａtｉcａllyusesthatbｌｏｃｋ'snamｅfoｒtｈenｅwfilｅ.7 InｔheＩnsertUｎitｓlisｔ,selecｔanｉnｓertunitｔouseiｎＡuｔｏＣADDesignCｅｎter．8 ChooｓeOK.Theblocｋdefiｎｉｔioｎiｓｓavｅｄasadｒawingｆile.InserｔingＢloｃｋsＹoucanｉnｓertｂlocｋsｏｒeｎtireｄrawiｎｇsiｎｔothecｕrrentｄraｗingwithINＳＥＲT.Whenyｏｕinsertaｂlockoｒdrawinｇ,yousｐecifｙtheinsertiｏｎpoiｎt,scａle，aｎdｒotationａngle.ThissectionexpｌaiｎｓinsertingbｌocksinｔｏyourｄrａwinｇｕsingINSERT.Sｅe"ＵsinｇAuｔｏCADDesｉgnCeｎtｅrｔｏInsertBｌocks."Whenyｏuinsｅｒtaｎentiｒedrａwingintoａnotｈerdｒaｗinｇ,AutoCＡDtreatstheｉnｓeｒteｄｄrawinglikｅaｎyｏtherｂlｏckｒefeｒence.Subｓｅquｅntinsertｉonsｒeｆeｒencetｈeblｏckdeｆiｎiｔion(ｗhｉchｃontａinsｔheｇｅoｍetｒicｄｅsｃriptioｎｏｆthebｌock)ｗｉｔｈdｉｆｆerentposition,sｃalｅ,andrｏtatｉｏnsettings,aｓshowｎintｈefolloｗingillusｔraｔｉon.Ifyoucｈangetｈeoｒｉｇinaldrawingafteｒinsｅrtingit,tｈeｃｈangeshａvenoeffectｏnｔheinsｅrteｄblocｋ.Ifyｏuwanttheinｓｅrteｄbｌockｔoｒｅflｅｃtthｅchangesｙoｕmaｄetｏｔheoriginaｌdrawｉnｇ，ｙoucａnｒｅdeｆｉnetheblockbyreinｓｅｒtiｎgｔheoriginａldrawing.Ｉfyouｗantｔｏｉnｓeｒｔadrawingbutｙoudon'ｔwaｎtｔｈeｆilenameｔｏbｅthesameasｔhebloｃknａmｅ,ｙouｃaｎｉｎsｅｒtitusiｎgａｂlockname=fiｌeｎamｅsｙntaxatｔｈｅBlockＮａmepromｐt.Bｙｄefaｕlt，ＡｕtｏCADusesthecooｒdinatｅ0，0，0ａstheinsｅrtioｎbaseｐointfｏｒinseｒteddraｗｉngs.YouｃanchangetｈeinsｅrｔionｂaseｐｏiｎｔｏfaｄrawingbｙｏpeninｇtheorigiｎalｄrａｗinganｄusｉngBASＥtospecifyadiffｅrｅntinsｅrtionbasepoｉnt.ＡutｏCADusesｔhenewbasepｏｉｎｔtｈeｎeｘｔｔiｍeyouinserttheｄｒaｗｉng.Ifｔｈedrawingyouiｎsertｃontainsｏbjectscreaｔedｉnapaｐeｒｓｐaｃelaｙoｕｔ，thoseoｂjectsareｎotｉncｌuｄediｎthecurreｎtdraｗing＇sbｌocｋdｅfinｉtｉon.Tousetheｐaｐerspaｃeｏbjｅctｓｉnaｎotheｒｄrawiｎg，opｅｎtｈeorｉｇiｎaldｒawingaｎｄuｓeBLOＣKｔodeｆinethepａｐerspaceｏbｊeｃtｓasablock.Ｔｈeblockisｎｏwdｅfineｄwｉthinyourｄrａwｉｎｇ.Yoｕcaninsertthｅdrawingintｏａnotｈerdrawingaｎdinsertｔhebloｃkdｅfineｄｉｎyｏurorｉginalｄrawiｎgｉneｉtherpaｐeｒｓpaｃeorｍｏdｅlsｐaｃe.WiｔhＡutoCADDesigｎCenter,youｃandispｌaylaｙoutsａnddragｔhemiｎtoyｏｕrdrawiｎgｓ.Sｅe"WorｋingwiｔhDrawingＣｏnｔeｎt．＂Toｉnｓｅｒtablockreｆeｒｅncｅ1ﻩFromtｈｅInｓｅｒtmｅnｕ,chooseBloｃｋ.2ﻩIntheIｎsertdialoｇbｏx,sｐecifyｔhｅｂlocknａｍｅ,ｗhereyｏuｗanｔtoinｓｅrｔiｔiｎtｈecurｒenｔdrａｗing,anｄwhetherｙouｗaｎｔtoexplodeitａfterinｓｅrtion．3ﻩIfｙｏuhａｖeｍodifｉedtheorigｉｎaldrawinｇｆｉlefoｒablｏｃk,ｙouｃanredefｉneｔhebloｃkinthecurrｅｎtdrawinｇbychoｏｓingFiletoｌｏcaｔｅthefilefｏrtheｂlｏcｋ.4 ChｏoseOK.Theblockreferｅnceisupｄatedinthecｕrrentｄraｗing.ExplodｉngａBlockUseEXPＬODEtobreakａblocｋinsｔａｎｃｅ.Ｂｙｅxplｏdｉnｇａblｏckinstanｃｅ,youcａｎmｏdifyｔheblockoraｄdtoｏrdｅleteｔｈeｏbjecｔｓtｈａｔdefineiｔ.1０.3ﻩWorkingｗiｔhAttriｂuｔｅｓAｎatｔｒiｂｕtｅpｒovidesalabelｏｒｔａgforｙouｔoatｔａchtｅxttoabｌｏck．Wｈeneverｙｏuｉｎsertablｏckthａthasavariａbleatｔribｕｔｅ，AｕtoCADprompｔsyoutoeｎterｔhedatａｔｏbesｔoredｗiththeblｏck.Examplｅsofｄatａareｐａrtnumbｅrs，ｐrices,ｃommｅnts,andowners＇ｎamｅｓ.Yｏucanextrａctaｔtｒibｕteiｎｆormaｔioｎfrｏmadｒａｗinganｄuｓethａtinｆoｒmationinaspreadsheetordaｔaｂasetoproduｃｅitemssuchａsapartslisｔorａbillofmateriaｌs(BOM）.Yoｕcanａssoｃｉatemorethanoneａtｔｒiｂutewｉthablock,pｒoｖｉdｅdｔhateaｃhattｒｉbｕteｈａｓａdifｆerｅnｔtag．AutoＣADpromｐｔsyoｕfoｒthevaｌｕｅofｅachattrｉbｕteｗheｎｙoｕiｎseｒtthebｌｏck.Yｏｕcaｎalｓodeｆｉｎecoｎstantattriｂutes:becａｕｓetheyhavethesaｍevaluｅinevｅryｏccurrenceofｔheblock,AutoCＡDdoｅｓnｏtpromｐｔforavaｌuewｈenｙouｉnserttheｂｌｏｃk.Attribuｔescanｂｅiｎｖisibｌe,whichmeanstheatｔributeｉsnotdisｐlayeｄorplｏtteｄ.However,informaｔｉoｎｏnｔheａtｔribｕteisｓtoｒediｎtｈedｒawｉngｆｉleanｄwrittｅｎtoａnｅxtractfilｅbyAＴTEXＴ．CｒｅａtｉｎｇAtｔrｉbｕｔesTocreateanａｔｔribute,ｙｏumustfｉrｓｔuｓｅAＴTDＥFｔocｒeateanattｒｉbuｔedｅfinition,wｈicｈdeｓcriｂesｔhｅchaｒacｔerｉsｔｉcsoftheattribｕte.Ｔｈｅcharactｅrｉstｉcsincluｄｅｔｈetag,prompt,valueｉｎfoｒｍatｉon,texｔformaｔtinｇ,ｌocaｔｉon,anｄanｙoptiｏnalｍodes.Tocreａtｅａnattｒｉbutedｅfiｎition1ﻩＯnthｅｃommａndlｉnｅ，enteｒattdeｆ．2ﻩInｔhｅAｔtｒiｂuｔeDｅfｉｎｉtｉondialogbｏｘ，ｓpeciｆyｔｈeｉｎsertｉonpoiｎｔaｎdｓｅttheattrｉbｕｔｅmodesanｄthetag,pｒompt,anｄｔextoptｉons．3ﻩCｈｏoseOＫ.Aｆtｅrcrｅatｉngtheatｔributｅdeｆinition,youｃansｅlｅｃtitaｓanoｂjectiｎablockdｅｆinitiｏn.Iｆtｈeattriｂutedeｆｉｎitｉonisincｏrｐorateｄｉntoａblocｋ,ｗｈeneveryoｕinseｒtthｅｂloｃk,AutoCADprｏmptsyouwithtｈｅtextstrｉｎgyｏuｓpecｉfｉedｆortheａtｔｒibute.Eａchsｕbsequenｔiｎstａｎｃeoｆthｅｂlockcanhaveadｉffｅrｅntvaluespecｉｆiedｆｏrtheａttribute.Ifyｏuwaｎttｏuseseｖeraｌattriｂｕteｓtｏgethｅr,ｃｒeａtｅeacｈonesepａratelyanｄtｈｅniｎcｌuｄethｅminthｅsameblｏｃk.Ｔｏcｏｎtrolｔheｏrｄerofpｒomptsformultipleatｔributｅs,ｓeｅＯＰTIONSinｔheCommaｎdＲefｅｒｅnce.ＳysｔemvａriａblesAFLAGSsetｓtheATTＤＥFｍode.ATＴDISPgloballycｏntrolｓthevisｉbilitｙofaｔｔributes.ＡTTREＤＥFrｅdefinesablocｋandupdatesaｓｓｏciatｅdaｔtｒibutes.EｄitingAttriｂutｅDefｉｎｉtiｏnsYｏｕcanｕseＤDＥＤITtoeditａｎattriｂutｅdefinitionbefｏｒeｉtisaｓsociaｔeｄｗithablock.Toediｔanａｔtrｉbuteｄefｉnitｉonbefｏｒeｉtｉsassociateｄwithａbloｃk1ﻩFroｍｔheMｏdifymenu,cｈｏｏsｅTｅxt２ Sｅleｃttheattribｕtｅtoｅｄｉt.3ﻩIntheEdiｔAttriｂｕｔeＤefiniｔｉonｄialogｂox，ｓｐｅciｆytｈeatｔribｕtｅｔag,prｏｍpt,anｄｄeｆaｕlｔvalｕe.ThenchooseOＫ．CｏmｍaｎdlineDDEDITReｌateｄCHANGEedｉｔsattrｉbutedefｉniｔｉonｓ．AｔｔａchｉngＡttｒｉbuｔestoBloｃkｓYoｕｃaｎattacｈattribｕｔestoablｏcｋwｈｅnyoｕdｅfinｅorｒedefinethaｔｂｌock.WｈenAutoＣADprｏｍptｓyoutoselecｔtheobjeｃtstoiｎｃludeｉntheblｏｃkdefiniｔiｏn,inclｕdetｈedｅｓiredａｔｔrｉｂｕｔesｉnthｅseｌectioｎseｔ.Ｔhｅｏrｄerｉｎwhicｈｙoｕｓeｌecｔthｅatｔributesdeｔｅｒmiｎeｓtheordeｒinｗhiｃhyoｕareproｍpteｄｆoｒａttriｂｕteinｆormatiｏnwｈenｙouｉnsｅｒttｈｅｂloｃk（ｓｅｅ"ＤeｆinｉnｇBｌockｓ＂）.EｄitingＡttｒibｕｔｅｓAtｔacｈeｄｔｏBlocksYｏｕｃanediｔatｔriｂｕtesｔhataｒealreadyattaｃheｄtoabloｃｋａnｄｉnｓertｅdinadrａwing.Toedｉｔanattｒibuteaｔtachedｔｏablocｋ1 FromtheModifymenu，chooｓeAttribuｔｅSinglｅ.2ﻩＳｅlｅctａbloｃkｔoediｔ．３ﻩIntheＥｄiｔAtｔribuｔesdialogboｘ,ｅdｉttｈｅａｔtribｕteinfoｒmaｔioｎａsｎeｃessary.４ ChooseＯK．Ｔｏcontｒoltｈeorderofprompｔｓｆoｒmultipｌeaｔtrｉｂutes,ｓｅeOＰTIONSinthｅCｏｍmａndRｅfeｒeｎcｅ．10.4UsｉngExteｒｎaｌRｅｆerenｃesAnexteｒnalrｅferｅｎｃｅ(ｘｒｅf)linkｓanｏｔherdrawinｇtothecｕrrentdraｗiｎg.Ｗｈｅｎyｏuinsertaｄrａwiｎgasaｂloｃk,ｔheblocｋdefinｉｔｉｏnandalloｆtheaｓsoｃiateｄｇeｏｍｅtryarestoredinthｅcuｒrenｔdｒawingｄａtabaｓe.Tｈebloｃｋisnoｔupｄａtｅdｉftｈｅoｒigｉnaldrawｉngchａnges．Ｗｈenyouinseｒtadrａwingasａｎxreｆ,howevｅr，tｈｅxrefｉsupdatedwhｅntｈeorigｉnaldrawｉngｃhanges.Aｄrawingcontaiｎingxrefsalwａｙsrefleｃtsthemｏstcuｒｒｅnteｄitinginｅacｈexｔernaｌlyreｆerencedfｉlｅ.Likｅａｂlockrefｅrence,aｎxrefisdispｌayｅｄinthecuｒrｅnｔdrａwingaｓａsｉnｇｌｅobject.Ｈowever,ａnxrｅfｄｏesｎｏtsigｎificantlｙincｒeaｓｅtｈｅfiｌesｉzeoｆtｈecurrｅntdrａwingandcanｎotｂeexpｌodeｄ.Aswithｂlocｋrefeｒences,youｃannestxrｅfｓthａtarｅａttａcｈedtoyourdｒaｗing.Byattachingxｒefs，yｏuｃanAssemｂleａｍａsterdｒawinｇfromcｏmpoｎentdrａwingsthａtｍayunderｇocｈanｇesasaprｏjectdｅveloｐｓ.Ｃｏｏrdinatｅyoｕrworｋwitｈtheｗｏｒkｏfoｔｈeｒsｂｙoverｌayｉngotｈerdrａｗｉｎｇsonｙouｒｄrawinｇtoｋeepｕｐwitｈtｈｅcｈangeｓｂｅｉngｍadｅbyothｅrｕserｓ.Eｎsurｅthattｈemoｓtrｅcｅｎtveｒsioｎofｔherｅferenceｄdrawingisdｉｓplayｅd.Wｈenyouoｐenoｒｐｌoｔｙoｕrｄrawｉng,AutoCADautoｍaｔｉcalｌｙｒeｌoadseacｈxｒef，sotheｄraｗingｒｅflｅｃtstｈeｌatesｔchaｎｇestoｔhｅｒeｆerenceddｒawingｆiｌe．Dｉsplaｙonｌyasｐecificｓectionｏfthexrefｆileinｔhemasｔeｒdraｗingbｙcrｅatinｇclｉｐpｅｄbouｎdarieｓｏｆxｒefs.10．5ＣｌipｐiｎgBlocksaｎdＸｒefsAｆtｅrattａchingaｄrａｗingaｓanｘreforinsertingablock,yoｕcandｅfineaclipｐiｎgbｏｕndａryｂyusｉngXCLIP．Aclippingbｏunｄａrｙcanｄefinｅａｐoｒtioｎｏfablockorｘｒeｆｗｈiｌeｓupprｅssingｔhedｉｓplaｙofgeoｍetryouｔsｉdｅoｆtｈeｂoundary.Cｌippｉngaｐpliestoaｎiｎdividｕalinstanｃeｏｆaｎｘreｆ,notthexrefdｅfiｎitionitsｅlf.Thepｏrtionofthｅxｒefｏrblocｋwithintheclｉｐｐedｂounｄaryrｅmaiｎsｖiｓiｂle,aｎdtｈｅremaｉnｄerofｔheｘrefoｒblockｂecomeｓinｖisiｂle.Tｈereferencedgeｏmetryiｓｎｏtalｔerｅd，ｏnlｙｔｈedisplayofｔhexreｆiseditｅd.YoucaｎuｓｅＸCLIPtｏcｒeａteanewclｉppiｎｇboundａry，dｅｌetｅanexｉstinｇboｕndary,orgenerateapolｙlineoｂjｅｃtcoiｎcｉdentwithvertｉcesofthｅcｌiｐpｉngｂｏｕndary．Xｒeｆclipｐinｇcanbetｕｒnｅdoｎoroff．Whenaclｉppingbounｄａryisｔurｎedｏff,theboｕndaｒｙisnotdｉsplａyedandtheｅntirexrefｉsviｓible,prｏｖidedthaｔｔhegeomｅｔryisonalayerthatｉsonanｄｔｈawed.Whｅnacｌｉppingboｕndaryistuｒnedｏff,itstｉｌlexistｓaｎdcaｎbｅｔurｎｅdon.Ｈowever,dｅletingaclippingboundaryispermanｅｎt.FｏrmoreinfoｒmaｔｉｏnａbouｔXCLＩP,seeｔｈeＣｏｍmandＲｅfｅrｅnｃe.Afteranxｒefｏｒblockhａsbeeｎｃlipｐｅd,itcａｎbｅeditｅd,ｍｏved,orcoｐieｄjustlikｅanuｎclippeｄxreｆｏｒblock.Ｔheｂoｕndarymovesｗitｈｔherefeｒence．Ifａnxreｆcｏｎtａiｎsnestedｃlippedxrｅｆs，thｅｙａppearcliｐｐediｎthedrａｗｉｎｇ.Ifｔhepareｎｔxｒefiｓｃｌippｅd，theneｓtｅdｘreｆsareａlsoclｉpped.Iｆyouwaｎｔtoseetｈeclｉpｐingｂｏuｎdary，youｃantｕrｎonthｅＸCLＩPFRＡMEｓｙｓｔeｍvａrｉable.XCＬＩPFRAMEdeｔerminesｗhetｈeｒtheclippingbounｄaryｆｒａｍeｉsdｉsplayed.Whenｔheclipｐｉngｆrameison(settｏ1),iｔcaｎbesｅlecｔeｄaｓｐarｔofthｅobjectanｄplotted.FoｒｍoreinfｏｒmａtioｎaｂoｕtＸCＬIPFRAME,seetheＣommａndRｅfｅrence.１0.６ＥditingRefｅrenｃeｓinＰlaceYoucanmodｉfyexｔｅrｎalreｆｅｒeｎcesanｄredefiｎebｌｏｃkdeｆinitionsfｒｏmwiｔhintｈecｕrrentdrawｉngbｙusinｇin-placeｒｅｆｅrenceｅditing．Ｂｏthbｌocksanｄxrefsaｒｅconsidｅrｅdrefereｎcｅｓ.Ofｔeｎ,ａdrawingcontainsoneｏrｍorｅxrefsaswｅllasmulｔｉpｌeblocｋｒｅfeｒences.Whｅnｗorｋｉｎgwithblocｋreferenceｓ,youcanseｌectablｏｃｋ,ｍｏｄiｆｙit,andupdatethebｌockｄｅfinｉtion.Whenworkingwitｈxrefs，ｙoucａｎuseｉn-plａceｒｅferｅnceedｉtingtｏseｌｅcｔtｈerｅferenｃeyｏuwaｎttoｗorkｗiｔh，modifyitｓｏbｊｅｃts,aｎdsavebａｃｋthｅchａnｇestothｅrｅfeｒｅncedrawing.Yｏｕcanｍaｋeminoｒｃhaｎgeswｉｔhouthaｖingtogｏｂaｃkan